The construction and manipulation of plasmids and of cloned DMA sequences is a central activity of every laboratory involved in the molecular analysis of cancer. Some manipulations are more challenging and some plasmids refractory to common procedures. The Molecular Biology Shared Resource was initiated to assist Cancer Center investigators with plasmid manipulations and cloning projects that prove problematic to individual laboratories or that prove refractory to manipulation by laboratory technicians, students, and post-docs. In addition, the Molecular Biology Shared Resource provides a cost-effective alternative to a variety of basic services to the investigators of the Massey Cancer Center (MCC). These basic services include endotoxin-free plasmid purification, insert purification, plasmid management and maintaining an inventory of plasmid vectors and clones. Other projects are designed upon the specific needs of client laboratories including custom subcloning, library screening, generation and optimization of protein expression vectors, design, construction, and analysis of gene targeting vectors, and protein production in bacterial, insect and mammalian cells. The MBSR works in synch with the Transgenic and Knockout Core Facility and facilitates access of Cancer Center members to such animals through vector design and construction. A large part of the activity of the Core involves plasmid manipulations that have proven difficult for the requesting laboratory, so each job tends to have unique characteristics and usually involves trouble-shooting and redesign of procedures. Thus, the expertise of Facility personnel has proven to be one of the most valuable services offered by the Core. MSBR personnel offer training seminars and previews of newer technologies as they are developed, and often train laboratory personnel in routine (and not so routine) molecular procedures. The Core Director offers a formal course in all phases of molecular technique that can be taken for credit or audited. New directions for the Molecular Biology Shared Resource are continuously being sought, in consultation with Cancer Center investigators and the MBSR oversight committee. The recent hire of new faculty in Chemical Biology into the Departments of Chemistry and Biochemistry (members of the Molecular Cancer Therapeutics program) has promoted a move towards the support of protein production for structural studies. The Shared Resource has been increasingly active during the past 2 years assisting investigators with their protein production needs, generating expression vectors and optimizing protein expression systems for scaled-up production.